Even in texts I don't use text speak, and don't know anyone that does. Unless you've just hit the character limit, it's just a disgrace as it has a powerful affect (or whatever the xkcd strip refers to, meh effect) on the rest of your writing skills. Whenever I try and correct someone over the internet on it, they just tell me to stop being a teacher/they don't need to use English/some other ludicrous excuse.
Take an extra 10 seconds out of your day to save me the time it takes for me to facepalm trying to read the thing. YOU'RE. THEIR.
It's also a sign that you didn't even bother to read what you wrote and it's clearly not important, whereas I actually reread what i've typed in case a) it looks stupid in which case I delete it or b) something can be misinterpretated (which happens frequently over teh interwebz).
Take an extra 10 seconds out of your day to save me the time it takes for me to facepalm trying to read the thing. YOU'RE. THEIR.
It's also a sign that you didn't even bother to read what you wrote and it's clearly not important, whereas I actually reread what i've typed in case a) it looks stupid in which case I delete it or b) something can be misinterpretated (which happens frequently over teh interwebz).